Topical Omidenepag Isopropyl Lowers Intraocular Pressure in Normal and Glaucomatous Cats: A Pilot Study.

PURPOSE: To evaluate the effects of topical prostaglandin E2 receptor 2 (EP2) agonist, omidenepag isopropyl (OMDI), on intraocular pressure (IOP) and pupil diameter (PD) in normal cats and cats with feline congenital glaucoma (FCG). ANIMALS STUDIED: Ten FCG cats and 8 normal cats. METHODS: In this prospective, randomized, placebo-controlled, masked pilot study, normal and FCG cats received one drop of 0.002% OMDI ophthalmic solution in one eye and artificial tears in the contralateral eye. IOP and PD were measured by a masked observer at baseline and at multiple time points up to 32-36 h post-administration. RESULTS: Topical 0.002% OMDI significantly lowered IOP compared to controls in both normal and FCG cats. In normal cats, the effect was significant up to 12 h after instillation, with a maximal reduction from baseline of 7.3 mmHg (43.5%). In FCG cats, the effect was significant from 2 to 8 h after instillation, with a maximal reduction from baseline of 16.7 mmHg (60.2%). No significant effect on pupil diameter or signs of ocular irritation was observed in either group. CONCLUSIONS: A single topical drop of 0.002% OMDI significantly lowers IOP in normal and FCG cats without inducing miosis. Our findings support that topical selective EP2 agonists may be a promising therapeutic option for feline glaucoma and provide information relevant to dosing intervals for future studies.